Information update regarding the investment agreement with Apache

To:

BUENOS AIRES STOCK EXCHANGE
Technical and Securities Exchange Office
Mrs. Nora Ramos

Your Offices

Ref.: C.R. 187637

Dear Sirs,

In my capacity as Responsible of Market Relations for Pampa Energía S.A. (“Pampa” or the “Company”), I address the Buenos Aires Stock Exchange in response to the note referenced above regarding the relevant event published by the Company on December 1, 2010 in relation to the investment agreement subscribed between a subsidiary of the Company, Petrolera Pampa S.A. (“Petrolera Pampa”), and Apache Energía Argentina S.R.L. (“Apache”).

In that sense, we inform that Petrolera Pampa together with Apache are successfully fulfilling this investment agreement and that, as of the date of this note, the production goal originally proposed has been achieved.

Kind Regards,

Ignacio Martín Meggiolaro
Responsible for Market Relations